1. Field of the Invention
The present invention relates to an apparatus for monitoring machine faults based on the operating status of machine such as construction machine, and more particularly to an apparatus allowing the amount of data to be reduced when operating status data are collected at a monitoring station to monitor faults based on such data.
2. Description of the Related Art
U.S. Pat. No. 5,400,018 is an example of an invention relating to the surveillance of faults such as drops in vehicle engine oil pressure or overheating based on the operating status of vehicles such as construction machine.
In this document, to monitor vehicle faults, data relating to the operating status from a vehicle are collected at a monitoring station, and a determination is made, on the basis of the collected data, whether or not to deal with the fault by repairing the vehicle, issuing an emergency stop command, or the like.
That is, when a fault such as a drop in engine oil pressure is detected in a vehicle, a fault (drop in engine oil pressure) code is generated, and the fault code is transmitted to a monitoring station. The monitoring station monitors a plurality of vehicles, and stores vehicle history data for each vehicle, such as the type of faults occurring in the past, the frequency of such faults, and the date on which they occurred.
When a fault code is transmitted from a vehicle, it is compared with the aforementioned vehicle history data. When it is determined that the fault code indicates an infrequently occurring fault (drop in engine oil pressure), a snapshot data request command is issued to the corresponding vehicle to conduct a detailed search of the status prevailing at the time the fault occurred so as to send snapshot data from around the time the fault occurred to the monitoring station. In cases where the fault indicated by the fault code is frequently occurring, snapshot data from when this type of fault has occurred will already have been stored at the monitoring station, and no request command is sent to the corresponding vehicle, on the assumption that the data are not significant.
Here, "snapshot data" refers to data from around a prescribed period of time at the time the fault is detected in a vehicle, which are the data of the vehicle operating parameters (engine rotational speed, speed, etc.) relating to the fault (such as a drop in engine oil pressure).
The vehicle receiving the request command transmits snapshot data from around the point in time at which the fault was detected to the monitoring station.
Thus, in conventional inventions, in cases where the same malfunction frequently occurs in the same machine, no snapshot data are requested of the vehicle so as to minimize the accumulation of data in the monitoring station.
In the aforementioned conventional technique, however, it is possible that snapshot data necessary for monitoring faults will be overlooked by the monitoring station because the determination as to whether or not snapshot data are needed is made merely by comparing the vehicle history data in which the type, frequency, date and the like of the fault indicated by the fault code are recorded in time sequence. It is also possible, on the other hand, that snapshot data which are not needed for monitoring faults will be requested.
That is, even though the same type of fault may have occurred frequently in the past, the circumstances under which it occurs vary, and the same fault is not necessarily produced under the same operating circumstances. Thus, even though the same fault may have occurred numerous times in the past under the same operating circumstances without impeding actual operations, the same fault occurring under different operating circumstances can fatally damage the vehicle. When, therefore, the need for snapshot data is determined solely on the basis of the past frequency of the fault, there is a risk that the vehicle could sustain major damage because of the inability to collect scarce snapshot data indicating the potential for fatal damage to the vehicle.